DES MOINES, Iowa (AP) — Des Moines police are continuing to investigate an early morning accident that occurred when a police car collided with another car in an intersection.

The Des Moines Register reports (http://dmreg.co/15UWxaE ) Monday that police haven’t determined if an officer had activated his patrol car’s lights and siren before entering an intersection early Saturday. Officer Mitchell Cameron Lee says he activated his lights before entering the intersection and hitting a car carrying five people.

All were injured.

An investigation is being hindered because equipment that usually would capture light and siren information had been removed for maintenance.

Des Moines Police Sgt. Jason Halifax says the officer still could be at fault regardless of whether lights were flashing because officers must ensure they’re driving safely upon entering an intersection against a red light.